Abstract
Oxidative stress to DNA from smoking was investigated in one randomized smoking cessation study and in 36 cohort studies from excretion of urinary 8-oxo-7-hydrodeoxyguanosine (8-oxodG). Meta-analysis of the 36 cohort studies showed smoking associated with a 15.7% (95% CL 11.0:20.3, p < 0.0001) increased oxidative stress to DNA, in agreement with the reduction of oxidative stress to DNA found in the smoking cessation study. Meta-analysis of the 22 studies that used chromatography methodology on 1709 persons showed a significant 29.3% increase in smokers (95% CL 17.3;41.3), but meta-analysis of 14 studies on 3668 persons using ELISA methodology showed a non-significant effect of 8.7% [95% CL −1.2;18.6]. Tobacco smoke induces oxidative damage to DNA; however, this is not detected with ELISA methodology. Currently, the use of existing ELISA methodology to measure urinary excretion of 8-oxo-7-hydrodeoxyguanosine cannot be recommended.
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Declaration of interest
The authors report no conflict of interest. The authors alone are responsible for the content and writing of the paper.
Our study was supported by a non-restricted grant from Region Hovedstaden, Denmark (HEP), and the Research Unit, Mental Health Service, Esbjerg, Region of Southern Denmark, Denmark (PKE).